Golang: Missing packages when compiling binary in docker environment

[hardishw]

Describe the bug
When compiling go binary in a docker environment, some packages are not provided when the OS differs between the host and docker environment, despite existing in the go.mod. See below.

[ERROR] Completed: Compile with Go - (environment:linux_docker, google.golang.org/grpc/internal/syscall) - google.golang.org/grpc/internal/syscall failed (exit code 1).
gopath/pkg/mod/google.golang.org/grpc@v1.55.0/internal/syscall/syscall_linux.go:29:2: could not import golang.org/x/sys/unix (open : no such file or directory)

Pants version
2.16.0rc0

OS
MacOS

[WorkerPants]

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[tdyas]

Given which package is showing the error, this is probably due to a mismatch in what build tags were applied for conditional compilation of the OS-specific code in that package.